I have been using Ubuntu since 2010 and I have no idea how to add apps to start up. Can’t we make it simple ? Maybe a list of applications is available when we click an " Add new " button. It is too complex right now.

What about the Startup Applications Preferences app? That should be installed by default at least in Ubuntu?

EDIT:
If you wonder what the last entry in the pic means: I had set xhost +si:localuser:root in my autostart app to still be able to run Synaptic under Wayland. I always opened it on the commandline by typing sudo synaptic that way.

But I shouldn’t have set that command globally for security reasons. And I wasn’t able to open synaptic by just clicking the icon.

The following method is FAR more elegant:

Just create a new script for Synaptic by typing

gedit admin:///usr/bin/synaptic-pkexec

(Don’t worry, you might have to enter your superuser password twice. That still seems to be a bug with the new and shiny gvfs admin backend)

Within the script file make sure that you add the xhost commands properly. The text should look like this: